I certainly can't give you advice on something like that. You need someone a lot smarter than I am.
There are so many questions:
1. are the pictures genuine or altered?
2. is this something from the past (if so, how long ago) or current?
3. is it possible this was a slip up, a temporary lapse, and the person has since repented?
4. how credible is your source, and what is his/her motivation for sending them to you?
5. how does
Proverbs 26:20 about a talebearer apply to the sender and to you?
6. Does "covering" a multitude of sin apply? ref
1 Peter 4:8
7. could this be an assignment for you to cover that person in prayer and let God reveal it in His own time?
for starters